The present invention relates to beverage cans having easy-open ends, and particularly to pressurized beverage containers for products such as beer and soft drinks. The invention particularly includes an improved can end that provides a visible, directed vent discharge.
Most consumers are familiar with metallic beverage containers having easy-open ends and containing soft drinks or beer. And, most consumers are equally familiar with the associated marketing efforts, including the use of various decorations, trademarks, markings, colors, shapes and other indicia on the cans used to differentiate among the contained products and the producers. Producers are constantly searching for ways to differentiate their product from those of others. In addition to the product, the package often serves as a significant feature of this differentiation.
Many of the metallic cans for holding beverages or other products are provided with easy-open can ends having attached pull tabs. The pull tab is attached to the can end by an integral rivet. The can end has a tear strip defined by a score. The pull tab is lifted and then pulled or torn to provide an opening defined by the tear strip through which the contents can then be poured. Consistent with ecological and safety considerations, the tear strip and tab, under normal conditions, remain connected to the can end.
When opening a carbonated or pressurized can, the consumer typically hears a venting from the can on lifting of the tab, and is aware that continued movement forces the tear strip, defined by the score, downwardly into the can. The score used in most cans today includes the formation of a vent region adjacent the rivet. Although it may appear to the consumer to be a single action of lifting and pulling the tab, basically this can end construction provides an initial opening of the score at the vent region in response to the lifting of the rivet by the tab. This action is followed by further fracture of the score line as a nose of the tab presses downwardly on the tear strip. In the can industry, this is often referred to as an initial xe2x80x9cpopxe2x80x9d followed by a xe2x80x9cpush.xe2x80x9d During the initial pop, pressure contained within the can is vented. This involves the venting of gas, typically carbon dioxide or nitrogen, which disperses broadly from the vent region generally laterally along the surface of the can end beneath the tab and into the surrounding environment. A purpose of the initial venting is to relieve pressure and avoid what is referred to as xe2x80x9cmissilingxe2x80x9d of the tear panel. Accordingly, it has been desired to broadly dissipate the vented gas. A typical easy-open can end construction, including an anti-missile feature, is taught in U.S. Pat. No. 5,738,237, incorporated herein by reference. Further, the industry has viewed the discharge from a container as an undesirable feature, as discussed in U.S. Pat. No. 4,928,845 which teaches a throttle device as a safety feature against spraying from the can. U.S. Pat. No. 4,741,451 discloses another structure wherein a closure block on the interior of a can holds a lever portion of a pull tab which is pulled away from an aperture to allow venting from the can.
Although beverage cans are quite common and used throughout the world every day, the manufacturing technology involved is far from simple, and the capital investment in manufacturing machinery and tooling to manufacture the cans and can ends is substantial. It is not uncommon, for example, to use a 13 station die set to produce merely the tab. Exemplary methods of tab construction are taught in U.S. Pat. No. 4,465,204, the contents of which are incorporated herein by reference. Once in operation at the large volumes and high speeds of the can making industry, the can makers prefer to avoid major changes to the manufacturing systems, equipment and tooling.
While use of easy-open cans is widely and well received, it is desirable to provide a can including an improved can end which not only functions in the easy-open manner described above, but which also provides an additional method of product differentiation. It is further desirable to provide such improved cans without excessive modification of existing can manufacturing processes, equipment and tooling.
This invention provides a can having an improved easy-open can end, and method of manufacturing the end, which discharges a visible mist on opening of a pressurized can. It provides this feature through structure which does not require excessive modifications of the can end or the can end manufacturing processes, equipment and tooling.
In preferred form merely the tab is modified. A typical tab includes a rearward finger portion and a forward nose portion. As is typical in the art, the tab is mounted to the can end by a rivet and positioned such that the nose extends over the tear strip which is defined by the score. The score includes a vent region which is positioned adjacent the rivet. A typical tab includes a face portion extending between the rivet and the nose. Accordingly, the face portion extends over the vent region of the score. In accordance with the invention, the face portion is provided with a raised section having an opening such as a circular hole. The raised section extends over the vent region such that upon lifting of the tab, most of the gas discharged from the vent region is directed generally upwardly into the volume defined by the raised section, and then through the opening in the raised section. The raised section and opening are sized and shaped to cause the gas to discharge through the opening as a visible mist.
While many configurations are possible, such as a hemispherical bubble having a circular hole, a preferred raised section is a semi-circular or crescent shaped structure having an opening which is elongated, circular or oval.
The modification of a typical prior art tab forming process can readily involve the addition of steps during or at the end of the tab forming manufacturing process whereby the raised section and opening are formed. As desired, new tabs can be specifically configured and positioned to provide a raised section which receives the vented gas and an opening through which it will be dispersed.